From 5b41173a40f0050a648cf96941050c1178767141 Mon Sep 17 00:00:00 2001
From: Daniel Lerch <36048059+daniel-lerch@users.noreply.github.com>
Date: Fri, 22 Mar 2024 16:02:47 +0100
Subject: [PATCH] Avoid duplicate email addresses

---
 src/TravelBlog/Controllers/RegistrationController.cs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/TravelBlog/Controllers/RegistrationController.cs b/src/TravelBlog/Controllers/RegistrationController.cs
index c82c5f0..f47ae26 100644
--- a/src/TravelBlog/Controllers/RegistrationController.cs
+++ b/src/TravelBlog/Controllers/RegistrationController.cs
@@ -28,6 +28,9 @@ public async Task<IActionResult> Post([EmailAddress] string mailAddress, [Requir
         if (!ModelState.IsValid)
             return View("Index", new RegistrationViewModel(mailAddress, givenName, familyName, "Deine Angaben sind unvollständig oder ungültig!"));
 
+        // Avoid duplicate registrations with different casing or Gmail domains
+        mailAddress = mailAddress.ToLowerInvariant().Replace("@googlemail.com", "@gmail.com");
+
         if (await subscriberService.Register(mailAddress, givenName, familyName))
             return View("Success", new RegistrationViewModel(mailAddress, givenName, familyName));
         else